Variable delivery vane oil pump

ABSTRACT

A variable delivery vane oil pump, is provided with a stator ( 10 ) eccentrically mounted about a rotor ( 9 ), which is adapted to turn about a longitudinal axis ( 6 ) thereof, and presents a plurality of grooves ( 15 ) radially outwardly opened and slidingly engaged, each, by a respective vane ( 17 ) the vanes ( 17 ) being arranged essentially in contact with the stator ( 10 ) by interposing a single sliding annular element ( 19 ).

TECHNICAL FIELD

The present innovation relates to a variable delivery vane oil pump.

In particular, the present innovation relates to a variable deliveryvane oil pump of the type comprising a rotor, which is mounted to turnabout its longitudinal axis, and presents a plurality of outwardlyradially open grooves; a stator, which extends about the rotor, and iseccentrically mounted with respect to the rotor itself; a plurality ofvanes, each of which is slidingly mounted inside a respective groove,and presents an outer edge arranged essentially in contact with thestator; and adjusting means for selectively controlling the eccentricitybetween the rotor and the stator and, therefore, the delivery of thepump.

BACKGROUND ART

The known variable delivery vane oil pumps of the type described abovepresent some drawbacks mainly deriving from the fact of presenting arelatively high sliding friction between the vanes and the stator.

DISCLOSURE OF INVENTION

It is the object of the present innovation to provide a variabledelivery vane oil pump, which is free from the aforementioned drawbacks.

According to the present innovation, there is provided a variabledelivery vane oil pump, as claimed in the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present innovation will now be described with reference to theaccompanying drawings illustrating a non-limitative embodiment examplethereof, in which:

FIG. 1 is a schematic longitudinal section of a preferred embodiment ofthe vane pump of this innovation;

FIG. 2 is a section taken along line II-II in FIG. 1; and

FIG. 3 is a section taken along line III-III in FIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to figures from 1 to 3, it is indicated as a whole by 1,a variable delivery vane pump, for feeding oil to a lubrication circuit(not shown) of an internal combustion engine (not shown) of a vehicle(not shown).

The pump 1 comprises a supporting case 2, which has an essentiallyparallelepiped rectangular section, and comprises, in turn, a firstplate 3 laterally limited by an essentially flat surface 4. The plate 3is provided with a cavity 5, which presents a longitudinal axis 6orthogonal to the surface 4, opens outwardly at the surface 4, and isaxially closed by a second plate 7 arranged in contact with the surface4 itself.

The pump 1 further comprises a power shaft 8, which is mounted throughthe plates 3 and 7 to turn about the axis 6, and carries a keyedcylindrical rotor 9, which is housed inside the cavity 5, and presents awidth, measured parallelly to the axis 6, essentially equal to the widthof the cavity 5, also measured parallelly to the axis 6.

The cavity 5 further houses inside a stator 10, which extends about therotor 9, presents a width, measured parallelly to the axis 6,essentially equal to the width of the cavity 5 also measured parallellyto the axis 6, and is internally limited by an essentially cylindricalsurface 11 arranged in eccentric position with respect to the rotor 9.

The stator 10 is hinged to the plate 3 to oscillate, with respect to theplate 3 itself and under the control of an adjusting device 12 of aknown type, about a fulcrum axis 13 parallel to the axis 6 and thereforeallowing to selectively control the eccentricity between the rotor 9 andthe surface 11.

The rotor 9 presents two cylindrical reciprocally opposite cavities 14,which are obtained coaxially to the axis 6, and one facing the plate 3and the other the plate 7, and is provided with a plurality of radialgrooves 15 (in the case shown, six grooves 15), which are obtainedthrough the rotor 9 parallelly to the axis 6, are uniformly distributedabout the axis 6, radially outwardly open at an outer surface 16 of therotor 9 coaxially to the axis 6, and further open axially outwardly atthe cavities 14.

Each groove 15 is slidingly engaged by a vane 17 presenting an outeredge 18, which extends parallelly to the axis 6, and is arrangedessentially in contact with the surface 11 of the stator 10 by arrangingan annular shoe 19 in between.

The shoe 19 presents a width, measured parallelly to the axis 6,essentially equal to the width of a vane 17 also measured parallel tothe axis 6, and circumferentially coupled both to the stator 10, and tothe vanes 17.

Each vane 17 axially projects from the respective groove 15 inside thecavities 14, and presents an inner edge 20, which extends parallel tothe axis 6, and is essentially arranged in contact with two annularelements 21, each of which is accommodated inside one of the cavities14, extends about the shaft 8, and presents a diameter larger than thediameter of the shaft 8 and smaller than the diameter of the respectivecavity 14 so as to float inside the respective cavity 14 itself.

Each pair of respectively adjacent vanes 17 circumferentially defines arespective pumping chamber 22, which is further limited radially by therotor 9 and by the shoe 19 and axially by the plates 3 and 7, is shiftedby the rotor 9 about the axis 6 and through a suction inlet 23 and adelivery outlet 24 of the oil, and presents, following the rotation ofthe rotor 9 about the axis 6 and the eccentricity between the rotor 9and the surface 11 of the stator 10, a variable volume.

Furthermore, with regard to this, it is important to state that thevolume of each chamber 22 at the inlet 23 and the outlet 24 and,therefore, the delivery of the pump 1 are selectively controlled byshifting the stator 10 about the axis 13 and, therefore, modifying theeccentricity between the rotor 9 and the surface 11 of the stator 10itself.

As shown in FIG. 2, each vane 17 comprises a plurality of foils 25 (inthe case shown, four foils 25), which are reciprocally overlapped, andare slidingly radially coupled one to the other to ensure a relativelyefficient fluidtight coupling between the vane 17 and the shoe 19.

According to a variation not shown, the shoe 19 is housed inside arespective cavity, which are obtained in the stator 10, and opensoutwardly at the surface 11, and projects outwardly from the respectivecavity to arrange itself in contact with the respective vanes 17.

The operation of the pump 1 is easily inferred from the abovedescription and does not require any further explanations.

1. A variable delivery vane pump, the pump comprising: a rotor, saidrotor being mounted to turn about a determined longitudinal axis, andsaid rotor presenting plurality of grooves outwardly radially open atone surface thereof, said surface being substantially coaxial to saidaxis; a stator, said stator extending about the rotor, and beingeccentrically mounted with respect to the rotor; a plurality of vaneseach of said vanes being slidingly mounted inside a respective one ofsaid groove, and presenting an outer edge facing the stator; an adjustorselectively controlling an eccentricity between the rotor and thestator; and a single annular sliding element arranged between the statorand an outer edge of at least one of the vanes.
 2. A pump according toclaim 1, further comprising the sliding element being slidinglycircumferentially coupled to the stator and to the vanes.
 3. A pumpaccording to claim 1 further comprising each vane at least two foilsreciprocally overlapping and slidingly coupled one to the other.
 4. Apump according to claim 1, further comprising two annular elements,which are arranged on opposite bands of the rotor parallelly to saidaxis, and extend about the axis; each vane axially projecting from arespective one of said groove and presenting an inner edge arranged incontact with said annular elements.
 5. A variable delivery vane pump,the pump comprising: a rotor, said rotor being mounted to turn about alongitudinal axis, and said rotor presenting a plurality of groovesopening outwardly at one surface, said surface being substantiallycoaxial to said axis; a stator, said stator extending about the rotorand being eccentrically mounted with respect to the rotor; a pluralityof vanes, each of said vanes being slidingly mounted inside a respectiveone of said groove, and presenting an outer edge facing the stator; andan adjustor selectively controlling an eccentricity between the rotorand the stator; each of said vane comprising at least two foilsreciprocally overlapped and slidingly coupled one to the other; and asingle sliding annular element being arranged between the stator and thevanes.